What does "was to" mean?
"Was to" in this context means "to be." However, Anne Marie is using this incorrectly. Her statement is a hypothetical/unreal situation. It is a hypothetical situation due to Anne Marie using "if" in the sentence followed by the verb, "to be." She is stating that this has not happened, but is telling everyone what she thinks will if she were to fall in love. She should have said, "If I were to fall in love..." The grammatical rule for a hypothetical/unreal situation is to change the tense of "was" to "were," even if the subject is in the third person. Unfortunately, grammar isn't always used correctly in spoken English.